Actually, its also a religous practice. According to Genesis:I oppose circumcision. It is barbaric, but not necessarily insane. I don't believe a parent should e able to alter the child in any way before the age of majority--no tattoos, no piercings, nothing. Only in the case of actual medical necessity should circumcision be allowed.
BTW--it's mostly the (male) doctor who recommends circumcision, and the father who wants it.
"And God said to Abraham, "As for you, you shall keep my covenant, you and your offspring after you throughout their generations. This is my covenant, which you shall keep, between me and you and your offspring after you: Every male among you shall be circumcised. You shall be circumcised in the flesh of your foreskins, and it shall be a sign of the covenant between me and you. He who is eight days old among you shall be circumcised. Every male throughout your generations, whether born in your house or bought with your money from any foreigner who is not of your offspring, both he who is born in your house and he who is bought with your money, shall surely be circumcised. So shall my covenant be in your flesh an everlasting covenant. Any uncircumcised male who is not circumcised in the flesh of his foreskin shall be cut off from his people; he has broken my covenant." (Genesis 17:9-14)
Of course, its just another thing that gets ignored by those that follow the NT.